This invention pertains to pressure regulators of the type used to control the pressure of a fluid usually in gaseous form as it is withdrawn from a receptacle where it is normally stored at high pressures, e.g. in excess of 500 psi. Such regulators are commonly employed to deliver the fluid to a point of use such as an oxygen mask or a welding torch from a cylinder of oxygen at delivery pressures of less than 150 psi. The fluid pressure regulator devices include a manually operable control knob for adjusting the desired delivery pressure regardless of the source pressure involved.
Pressure regulators of the type disclosed in this application are illustrated by U.S. Pat. Nos. 2,115,512, 2,156,823, 2,487,650, 2,614,573, 2,747,607, 2,908,158, 2,918,081, and 3,547,143. In particular, the regulator of this invention is an improvement over the fluid pressure regulators disclosed in U.S. Pat. Nos. 2,918,081 and 3,536,092, which patents are owned by the Assignee of the present invention.
With the prior art regulators such as shown in U.S. Pat. No. 2,918,081, when the regulator is used to control the delivery of oxygen from a high-pressure source, which source is usually in excess of 500 psi, if there are contaminants inside the regulator such as grease, rust, or hydrocarbons in the presence of pure oxygen, these contaminants will act as fuel. The regulator materials such as elastomeric materials used to provide the valve seat will under certain conditions ignite to act as fuel. For example, ignition energy can be supplied by heat of recompression which is heat generated by the expansion and sudden compression of oxygen or by particles of contamination impinging on the internal surfaces of the regulator. This condition can exist when a regulator valve is opened rather quickly. If this condition does exist and ignition takes place, the seat is consumed with the resultant explosion of the regulator. While such explosions are rare, they nonetheless do happen.